Hospitals, nursing homes, and other patient care facilities typically include patient monitoring devices at one or more bedsides in the facility. Patient monitoring devices generally include sensors, processing equipment, and displays for obtaining and analyzing a medical patient's physiological parameters such as blood oxygen saturation level, respiratory rate, pulse, and a myriad of other parameters, such as those monitored on commercially available patient monitors from Masimo Corporation of Irvine, Calif. Clinicians, including doctors, nurses, and other medical personnel, use the physiological parameters and trends of those parameters obtained from patient monitors to diagnose illnesses and to prescribe treatments. Clinicians also use the physiological parameters to monitor patients during various clinical situations to determine whether to increase the level of medical care given to patients.
Examples of non-invasive patient monitoring devices include pulse oximeters. Pulse oximetry is a widely accepted noninvasive procedure for measuring the oxygen saturation level of arterial blood, an indicator of a person's oxygen supply. A pulse oximeter generally includes one or more light sources transmitting optical radiation into or reflecting off through a portion of the body, for example a digit such as a finger, a hand, a foot, a nose, an earlobe, or a forehead. After attenuation by tissue and fluids of the portion of the body, one or more photodetection devices detect the attenuated light and output one or more detector signals responsive to the detected attenuated light. The oximeter may, in various embodiments, calculate oxygen saturation (SpO2), pulse rate, a plethysmograph waveform, perfusion index (PI), pleth variability index (PVI), methemoglobin (MetHb), carboxyhemoglobin (CoHb), total hemoglobin (tHb), glucose, and/or otherwise, and the oximeter may display on one or more monitors the foregoing parameters individually, in groups, in trends, as combinations, or as an overall wellness or other index. An example of such an oximeter, which can utilize an optical sensor described herein, are described in U.S. application Ser. No. 13/762,270, filed Feb. 7, 2013, titled “Wireless Patient Monitoring Device,” U.S. application Ser. No. 14/834,169, filed Aug. 24, 2015, titled “Wireless Patient Monitoring Device,” and U.S. application Ser. No. 14/511,974, filed Oct. 10, 2014, titled “Patient Position Detection System,” the disclosures of which are hereby incorporated by reference in their entirety. Other examples of such oximeters are described in U.S. application Ser. No. 09/323,176, filed May 27, 1999, titled “Stereo Pulse Oximeter,” now U.S. Pat. No. 6,334,065, the disclosure of which is hereby incorporated by reference in its entirety.
In noninvasive devices and methods, a sensor is often adapted to position a portion of the body proximate the light source and light detector. In one example, noninvasive sensors often include a clothespin-shaped finger clip that includes a contoured bed conforming generally to the shape of a finger. An example of such a noninvasive sensor is described in U.S. application Ser. No. 12/829,352, filed Jul. 1, 2010, titled “Multi-Stream Data Collection System for Noninvasive Measurement of Blood Constituents,” now U.S. Pat. No. 9,277,880, the disclosure of which is hereby incorporated by reference in its entirety. In another example, noninvasive sensors can include one or more sensing components, such as the light source and/or the photodetectors on an adhesive tape, such as described in U.S. application Ser. No. 13/041,803, filed May 7, 2011, titled “Reprocessing of a physiological sensor,” now U.S. Pat. No. 8,584,345, the disclosure of which is hereby incorporated by reference in its entirety.
The patient monitoring devices can also communicate with an acoustic sensor comprising an acoustic transducer, such as a piezoelectric element. The acoustic sensor can detect respiratory and other biological sounds of a patient and provide signals reflecting these sounds to a patient monitor. An example of such an acoustic sensor, which can implement any of the acoustic sensing functions described herein, is described in U.S. application Ser. No. 12/643,939, filed Dec. 21, 2009, titled “Acoustic Sensor Assembly,” and in U.S. Application No. 61/313,645, filed Mar. 12, 2010, titled “Acoustic Respiratory Monitoring Sensor Having Multiple Sensing Elements,” the disclosures of which are hereby incorporated by reference in their entirety. An example of such an acoustic sensor is also described in U.S. application Ser. Nos. 13/762,270, 14/834,169, and 14/511,974 referenced above.